Molecular mechanisms of (-)-gossypol-induced apoptosis in human prostate cancer cells. Anticancer Res 2006;26(3A):1925-33
Date
07/11/2006Pubmed ID
16827126Scopus ID
2-s2.0-33745603202 (requires institutional sign-in at Scopus site) 60 CitationsAbstract
BACKGROUND: Gossypol, a natural compound present in cottonseeds, displays antiproliferative and pro-apoptotic effects against various cancer cells. The (-)-gossypol enantiomer is a more potent inhibitor of cancer cell growth. Here, the molecular mechanisms of apoptosis induced by (-)-gossypol were studied in human prostate cancer cells.
MATERIALS AND METHODS: After the prostate cancer cell DU-145 had been treated with (-)-gossypol, the trypan blue exclusion assay and DNA fragment end-labeling assay were used to stain the dead cells and to detect DNA laddering, respectively. The effects of (-)-gossypol on the expression of apoptotic-regulated gene markers in both death receptor- and mitochondria-mediated apoptotic pathways, such as the Bcl-2 family and caspase, etc., were detected by RT-PCR and Western blot analysis. To further investigate the apoptotic pathways induced by (-)-gossypol, different caspase inhibitors were used to block caspase activities and cell viability was detected by the CellTiter 96 AQueous assay in DU-145 cells.
RESULTS: At a 5-10 microM dose-level, (-)-gossypol significantly enhanced apoptosis measured by DNA fragmentation. (-)-Gossypol caused apoptosis in DU-145 cells through the down-regulation of Bcl-2 and Bcl-xL and the up-regulation of Bax at the mRNA and protein levels. (-)-Gossypol also activated caspases-3, -8 and -9 and increased PARP [poly (ADP-ribose) polymerase] cleavage. Furthermore, (-)-gossypol-induced apoptosis might be due to an increase in CAD (caspase-activated deoxyribonuclease) proteins and a decrease in ICAD (inhibitor of CAD) proteins. By using caspase inhibitors, (-)-gossypol caused apoptosis via the caspase-dependent pathways.
CONCLUSION: Our results indicated that the apoptotic processes caused by (-)-gossypol are mediated by the regulation of the Bcl-2 and caspase families in human prostate cancer cells. Our data also suggested that (-)-gossypol may have chemotheraputic benefits for prostate cancer patients.
Author List
Huang YW, Wang LS, Chang HL, Ye W, Dowd MK, Wan PJ, Lin YCMESH terms used to index this publication - Major topics in bold
ApoptosisCaspases
Cell Line, Tumor
Enzyme Activation
Gossypol
Humans
Male
Poly(ADP-ribose) Polymerases
Prostatic Neoplasms
Proto-Oncogene Proteins c-bcl-2
RNA, Messenger